The block enables you to specify lookup tables for these engine
characteristics. The lookup tables, developed with the Model-Based
Calibration Toolbox™, are functions of commanded torque,
Tcmd, brake torque,
Tbrake, and engine speed,
N. If you select Input engine temperature, the tables
are also a function of engine temperature,
TempEng.

Table

Input Engine
Temperature Parameter Setting

off

on

Power

ƒ(Tcmd,N)

ƒ(Tcmd,N,TempEng)

Air

ƒ(Tbrake,N)

ƒ(Tbrake,N,TempEng)

Fuel

Temperature

Efficiency

HC

CO

NOx

CO2

PM

To bound the Mapped SI Engine block output, the
block does not extrapolate the lookup table data.

Virtual Calibration

If you have Model-Based
Calibration Toolbox, click Calibrate Maps to virtually calibrate the 2D lookup
tables using measured data. The dialog box steps through these tasks.

Task

Description

Import firing data

Import this firing data from a file. For more information, see
Using Data (Model-Based Calibration Toolbox).

Turbocharger Lag

To model turbocharger lag, select Include
turbocharger lag effect. During throttle control, the time constant
models the manifold filling and emptying dynamics. When the torque request requires a
turbocharger boost, the block uses a larger time constant to represent the turbocharger lag.
The block uses these equations.

Dynamic torque

dTbrakedt=1τeng(Tstdy−Tbrake)

Boost time constant

τbst={τbst,rising when Tstdy>Tbrakeτbst,falling when Tstdy≤Tbrake

Final time constant

τeng={τthr when Tbrake<fbst(N)τbst when Tbrake≥fbst(N)

The equations use these variables.

Tbrake

Brake torque

Tstdy

Steady-state target torque

τbst

Boost time constant

τbst,rising,
τbst,falling

Boost rising and falling time constant,
respectively

τeng

Final time constant

τthr

Time constant during throttle control

ƒbst(N)

Boost torque speed line

N

Engine speed

Fuel Flow

To calculate the fuel economy for high-fidelity models, the block uses the volumetric fuel flow.

Qfuel=m˙fuel(1000kgm3)Sgfuel

The equation uses these variables.

m˙fuel

Fuel mass flow

Sgfuel

Specific gravity of fuel

Qfuel

Volumetric fuel flow

Power Accounting

For the power accounting, the block implements these equations.

Bus Signal

Description

Equations

PwrInfo

PwrTrnsfrd — Power transferred between blocks

Positive signals indicate flow into block

Negative signals indicate flow out of block

PwrCrkshft

Crankshaft power

−τengω

PwrNotTrnsfrd — Power crossing the block
boundary, but not transferred

EngTrq — Engine brake torquescalar

Parameters

Block Options

Include turbocharger lag effect — Increase time constantoff (default)

To model turbocharger lag, select Include
turbocharger lag effect. During throttle control, the time constant
models the manifold filling and emptying dynamics. When the torque request requires a
turbocharger boost, the block uses a larger time constant to represent the turbocharger lag.
The block uses these equations.

Dynamic torque

dTbrakedt=1τeng(Tstdy−Tbrake)

Boost time constant

τbst={τbst,rising when Tstdy>Tbrakeτbst,falling when Tstdy≤Tbrake

Final time constant

τeng={τthr when Tbrake<fbst(N)τbst when Tbrake≥fbst(N)

The equations use these variables.

Tbrake

Brake torque

Tstdy

Steady-state target torque

τbst

Boost time constant

τbst,rising,
τbst,falling

Boost rising and falling time constant,
respectively

τeng

Final time constant

τthr

Time constant during throttle control

ƒbst(N)

Boost torque speed line

N

Engine speed

Dependencies

Selecting Include turbocharger lag effect enables
these parameters:

Boost torque line,
f_tbrake_bst

Time constant below boost line,
tau_thr

Rising torque boost time constant,
tau_bst_rising

Falling torque boost time constant,
tau_bst_falling

Input engine temperature — Create input portoff (default) | on

Select this to create the EngTemp input port.

The block enables you to specify lookup tables for these engine
characteristics. The lookup tables, developed with the Model-Based
Calibration Toolbox, are functions of commanded torque,
Tcmd, brake torque,
Tbrake, and engine speed,
N. If you select Input engine temperature, the tables
are also a function of engine temperature,
TempEng.

Table

Input Engine
Temperature Parameter Setting

off

on

Power

ƒ(Tcmd,N)

ƒ(Tcmd,N,TempEng)

Air

ƒ(Tbrake,N)

ƒ(Tbrake,N,TempEng)

Fuel

Temperature

Efficiency

HC

CO

NOx

CO2

PM

Configuration

Calibrate Maps — Calibrate tables with measured dataselection

If you have Model-Based
Calibration Toolbox, click Calibrate Maps to virtually calibrate the 2D lookup
tables using measured data. The dialog box steps through these tasks.

Task

Description

Import firing data

Import this firing data from a file. For more information, see
Using Data (Model-Based Calibration Toolbox).